The plan is to allow for trading of carbon "offsets" on an open exchange. A company which purchased two billion tons in offsets could pump the same amount of carbon dioxide into the atmosphere without penalty. The offsets are generated by projects which save energy or reduce atmospheric CO2, such a reforestation.

It's good news for the likes of Joseph Farms in Merced County, which could potentially recoup costs from a system which turns methane from livestock waste into electricity.

But that cow-manure project represents only 25,000 metric tons of emissions spared. To offset the maximum allowed to polluters under the trading program, over 72,500 such facilities would need to be built.

At $3 million per installation, it would require offsets to cost nearly $109 a ton. The going rate at existing exchanges is a little over $3 a ton.

If the carbon offsets continue to be so inexpensive, the level of emissions could actually rise under the program, according to estimates by researchers from Oakland's Breakthrough Institute.

In the end, no alchemy of can-do entrepreneurial spirit or regulatory rule making will be turning cow pies into green gold anytime soon.